susurrus \su-SUHR-uhs\, noun: A whispering or rustling sound; a murmur.
Still, the breeze is soothing, as is the susurrus of the branches. --Michael Finkel, 'Tree Surfing and Other Lofty Pleasures,' [1]The Atlantic, March 1998
And there came, like the dry susurrus of wind before thunder peals and lightning, a great rustle of excitement. --Richard Whittington-Egan, 'The Edwardian literary afternoon: part one,' [2]Contemporary Review, April 2000
He heard the susurrus of curtains luffed by the breeze. --Erik Larson, [3]Isaac's Storm __________________________________________
Susurrus comes from the Latin susurrus, 'a murmuring, a whispering, a humming.'